1. Field of the Invention
The present invention relates generally to providing improved service in a communication system. More particularly, the invention relates to a method and apparatus for providing random access detection.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
Communication systems that transmit and receive communication signals continue to grow in importance. Such systems are used to provide television, radio, satellite communication, cell phone service, wireless computing networks and the like. An important aspect of such systems is the ability to efficiently detect when a user is seeking access to a communication system. In a communication system in which a user may attempt to access system resources at any time, a random access detector may be employed to detect when users are attempting to access the system.
Random access is a powerful and commonly used multiple access scheme that allows for multiple users to share the same resources, such as bandwidth and time, in a distributed fashion. The access scheme may be based on minimal feedback from the access point to the different users. The application and utility of random multiple access protocols are well established in both wired and wireless networks.
In a typical wireless cellular system (such as the Universal Mobile Telecommunications System, or UMTS), there are different co-existing schemes for multiple access, such as dedicated code-division for voice, scheduled time/code division for high speed packet data, and random multiple access. In these systems, random access is usually the basis on which a dedicated connection is set up. Apart from initial access into the system, this protocol may also be used in some low and moderate bit-rate data applications.
The efficacy of the random access channel is measured in terms of how long a user has to wait before gaining access to a system (ability to make a call), how much power it expends in doing so, and also from the system's point of view, how many such random accesses can be serviced (throughput), and (to a lesser degree) how much resources get wasted in setting up false connections. System performance parameters such as throughput and delay, which shape the user experience, are directly affected by system settings, such as initial transmit power levels, feedback delays, protocol for retries, false-alarm probability, power ramping step size, number of available access slots and signatures, gaps between consecutive transmissions and the like. However, one of the most important factors that determine these system parameters is the efficacy of the physical layer detector that is employed at the base station receiver. A random access detector that improves system availability is desirable.